Pavement heater



March 16, 1965 Filed April 2, 1962 E. B. DENTON PAVEMENT HEATER 3 Sheets-Sheet 1 ERIC B. DENTON INVENTOR.

ATTORNEY March 16, 1965 E. B. DENTON PAVEMENT HEATER 3 Sheets-Sheet 2 Filed April 2, 1962 2N mom 2m 2m 2N &- 0 2N N8 mow m5 ERIC B. DENTON ATTOR/VEKE March 16, 1965 E. B. DENTON PAVEMENT HEATER 3 Sheets-Sheet 3 Filed April 2, 1962 ERIC B. DENTON INVENTOR Y 30AM;

ATTORNEY United States Patent 3,173,413 PAVEMENT HEATER Eric B. Denton, Seattle, Wash, assignor, by mesne assignments, to Weyerhaeuser Company, Tacoma, Wash, a corporation of Washington Filed Apr. 2, 1962, Ser. No. 184,292 10 Claims. (Cl. 126-2712) This invention relates to a new and novel concept in a mobile pavement heater and more particularly to a mechanism carrying a series of radiant heaters for spot heating road surfaces so that traffic markers may be applied thereto.

The current trend toward the use of reflective traffic markers or buttons in place of conventional stripe painting requires new equipment for and methods of installation. The markers are usually made of solid, reflective, impact resistant, plastic material such as a synthetic resin, particularly alkyd or polyester type resin. These markers form a semipermanent installation calculated to function for five to twenty years. A particularly effective adhesive for bonding the markers to the road surfaces is based upon synthetic polyepoxide resins. This adhesive is a thermosetting type which when placed between the marker and road surface will set or cure in five to ten minutes thereby providing a bond between the marker and road surface which is usually stronger than concrete. To provide rapid cure for a thermosetting resin adhesive it is desirable that the adhesive be heated above normal atmospheric temperatures. It is particularly useful to heat the surface of the road or pavement before the adhesive is spread and the marker pressed on to the adhesive. This invention is designed to preheat the appropriate spots on the pavement surface in order to prepare such spots for application of the markers.

This invention adapts itself to the marker type traflic lane system in that it is simple framework on Wheels carrying a plurality of radiant heater units. The individual heater units are arranged in line and are adapted to be raised for moving the heater itself and to be lowered for the actual heating operation. The pavement heater carries a fuel tank forming a common source from which the individual heater units are supplied with fuel such as propane.

Accordingly it is a prime object of this invention to provide a pavement heater which will simultaneously heat a series of correctly spaced and aligned spots of road surface for the application of traffic markers.

Another object of this invention is to provide a pavernent heater which permits the individual heaters attached thereto to be spaced at any desired distance from each other.

Still another object of this invention is to supply a pavement heater which is mobile and easily moved over the road surface.

Yet another object of this invention is to provide a pavement heater which permits its individual heater units to be raised and lowered with a minimum of inconvenience and elfort.

A still further object of this invention is to furnish a pavement heater which is light and strong and easily movable from one job site to another and which in addition is simple in design and inexpensive to construct.

Yet a further object of this invention is to provide a pavement heater which is operable by a single person.

These, together with other objects and advantages which will become subsequently apparent, reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings, forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIGURE 1 is a perspective view of this invention showing the lower frame in the down position thus placing the heater units on the road surface;

FIGURE 2 is a side elevational assembly View of the pavement heater with the heater units in their lowered position;

FIGURE 3 is a top plan view of this pavement heater to more accurately illustrate overall length and width, wheel support construction, and heater unit location;

FIGURE 4 is an elevational front end view taken along line 44 of FIGURE 2;

FIGURE 5 is an elevational cross section view taken along the line of 55 of FIGURE 2;

FIGURE 6 is a schematic diagram of the pressurized fuel piping system which also actuates the lifting cylinder;

FIGURE 7 is a partial side elevational view of the rear or operating end of this invention showing the odometer and its supporting arm;

FIGURE 8 shows a top plan view of an alternative embodiment of a pavement heater in which only two heater units are mounted thereon;

FIGURE 9 is a side elevational view of the device of FIGURE 8 showing the heater units in their lowered position; and

FIGURE 10 is an end elevational view of the device of FIGURES 8 and 9 showing the heater units in their lowered position.

Referring now to FIGURES 1 to 3 it will be seen that the mechanism of this invention is principally comprised of two long, horizontal and parallel frame tubes or pipes, the upper of which is designated by number 12 and the lower of which is generally shown by number 14. The upper frame tube 12 is made of front section 16 and rear section 13 and the lower frame tube 14 is made of front section and rear section 22. Each of the frame tube members 12 and 14 is about 16 feet long. The two sections of which each main frame tube is made are approximately of equal length. The two upper sections 16 and 18 are threadably joined and detachable at union 24. Likewise the two lower sections 2t) and 22 are detachably joined at union 26. It will be noted that the upper frame tube 14 is sealed at both ends by pipe caps 28 and 30. Function of the sealed upper frame tube 12 will be more fully discussed hereinafter.

The two main frame members, i.e. frame tubes 12 and 14, are attached to each other by virtue of lifting arms 32. The precise details of lifting arms 32 are not important to an understanding of this invention. Sufiice it to say that each lifting arm 32 is comprised of two parallel bars 34 attached to each other by an X-shaped connector or link 36 (see particularly FIGURES 3 and 4). ()verall dimensions of the preferred embodiment of the lifting arms are a length of about 14 inches and a width in the area of 5 inches.

FIGURES 2, 5 and 7 indicate most clearly that all components of the complete pavement heater are attached to the two cylindrical frame tube members by virtue of a series of clamps 38. The clamps 38 are formed of top and bottom brackets secured together and on the frame tubes by bolts. For instance, FIGURE 7 shows that top bracket 40 and bottom bracket 42 are simple channel pieces with the two channel walls cut to conform to the cylindrical configuration of each of the two frame tubes. The brackets are then secured to the frame members 12 and 14 by bolts 44 on each side of the frame member. Since the various elements that make up the complete heater are supported by one or more clamps 38 the clamps will vary somewhat but remain basically the same.

The lifting arms 32 are pivotally secured to a clamp 38 on the upper frame tube and extend downwardly and rearwardly toward the operators end of the heater at about a angle from the vertical. The lower end of the lift'ng arms 32 is pivotally connected to a clamp 38 on the bottom frame tube. There are four lifting arms in the preferred embodiment of this invention spaced along the length of the heater though quite obviously such number could vary. One of the four lifting arms is in effect an actuating arm but functions otherwise in the same manner as arms 32.

The actuating arm, generally designated by number 46, is also comprised of side bars and X-shaped connector or link 36. However, arm 46 has as an integral part thereof extension bars 43 which extend from the upper end of side bars 3 and which are substantially shorter than said bars 34-. Said extension bars 48 are approximately inches long and extend upwardly and backwardly to form an angle of about 120 with bars 34. A cross bar 5t: (see FIGURE 3) connects extension bars 43 a short distance above the top of upper frame tube 12.

An air or gas operated actuating cylinder, generally shown by number 52, is affixed to upper frame tube 12. The main cylinder housing 69 has a yo (e 54 fixedly attached to its rear end. Yoke 54 in turn is pivotally connectcd to an upstanding bracket 56 which is rigidly secured to a clamp 38 and which is designed to fit between the two arms of the yoke 54. The cylinder piston 58 is pivotally attached to the cross bar of actuating arm 46. Thus, it will be understood that when the cylinder and piston are actuated to drive the piston 58 out, the actuating arm 46 pivots about its connections with the clamps 33 to swing the lower frame tube 3.4 upwardly toward the upper frame tube 12.

Tie basic framework described above is made mobile by the addition of two wheel supporting structures attached to upper frame tube 12. Such wheel supporting structures are best shown in FIGURES 2, 3 and 5. The rear wheel structure, generally designated by reference number 62, is located approximately halfway between the midpoint and rear end of the frame. The wheel structure in general is in the form of an inverted U with the legs sloping outwardly. The wheel structure 62 is formed of double spaced apart structural angle members. Two spaced apart horizontal frame pieces 68 are anchored to two frame clamps C28 and strengthened by a fiat plate 70. The pieces 6? are about 1 foot long. Extending downwardly and outwardly from each of said horizontal frame pieces 63 are two leg members 64, thus giving four such leg members. The free ends of leg members 64 are securely attached to wheel plates 66 to add rigidity to each side of the wheel structure and to provide a base support means for the casters '74. The rear wheel structure 62 is provided with swivel casters and to that end swivel yokes 72 are attached to wheel plates 66 Casters 74 are mounted in the yokes '72 in the usual manner. One of the caster units '74 may be provided with a footbrake (not shown) to aid in holding the heater frame in position on the road.

The forward or front wheel-support structure, generally shown by reference number 76, is located approximately halfway between the midpoint and the front end of said heater frame and is constructed similarly to rear wheel structure 62. Front wheel structure '76 has horizontal frame pieces 80 to the ends of which are attached leg members 78. Wheel plates 84 are connected to the free ends of legs '78 and carry fixed yokes 86 and wheels 83.

Lower frame tube 14 is designed to carry the individual heater units 90. As can be seen the lower brackets 42, of the clamps 38 which support the heater units, extend slightly to one side of the frame. It will be apparent to those skilled in the art that if necessary two heaters could be mounted on each clamp 38. It will also be obvious that mounting the heater units to one side is purely a matter of choice since the frame could be so constructed as to mount them in a centered position with respect to frame tubes 12 and 14. Upstanding brackets on the heater units have holes therein which align with holes in brackets A pin is inserted in the aligned 4 holes to accomplish a loose and detachable mounting of a heater 99 on a clamp 38. All clamps 38, of course, are capable of being moved along the length of either frame tube. Thus the heaters may be spaced from each other at any distance desired. Heater units obviously may be added or removed according to the need.

It has been found that a gas-fired radiant heater unit performs best for spot heating the road surfaces in a short period of time. Such a heater unit does not heat by virtue of a direct flame. Instead the combustion beats a ceramic burner element which in turn heats the road surface. This type of heater gives off an intense infrared radiation thereby increasing its effectiveness. With the heaters attached to lower frame tube 14 it will be understood that the heater units will be raised and lowered with such bottom frame tube.

An operators push handle 92, attached at an angle to an anchoring plate 94 is provided at the rear end of this device. The anchoring plate, as with all other components of this pavement heater is secured to two clamps 38. The push handle 92 slopes rearwardly and upwardly at about a 30 angle so that the handle grips 96 are approximately 36 inches above the road surface.

Immediately back of the rear wheel structure and attached to the upper frame tube is a fuel tank support cradle or carrier generally referred to by number 9%. Sai tank carrier is made up of a flat washer-shaped plate 16% secured to two clamps 38. Three upstanding posts Th2 are evenly spaced about the perimeter of said plate, and a holding strap we is connected to the upper free ends of said posts to complete said tank support. A simple cinching mechanism (not shown) is included with said holding strap 104 in order to firmly hold a container such as a propane bottle in said fuel tank support.

As was explained above the top frame tube 12 is sealed at both ends by pipe caps 28 and 30. This frame tuoe serves not only as a primary support element but also as a manifold or header for conveying fuel gas from the supply bottle via an appropriate control system to the individual heater units 90. It will be observed that at spaced intervals along the length of frame tube 12 there are a series of fuel supply outlet valve connections 1% tapped into the side of frame tube 12. There will be one valve con ection 1% for each heater. The preferred embodiment shows six heater units and a corresponding number of six valve outlets 196 though the number may vary as desired. A hose or line 108 connects each valve outet 1% with a heater unit )0. Thus the upper tube frame 12 acts as a header or manifold through which fuel gas may be conveyed to the hoses attached to the individual heater units 99.

FIGURE 6 shows that the pressurized fuel which in the preferred embodiment is propane, is supplied in a tank 11% mounted in the carrier 98. A hose or line 112 is connected at one end to a valve 114 on the tank and at its other end is tied in to a primary pressure reducing valve 115. The outlet of reducing valve 116 is connected by a short line 113 to a line or conduit 120. Line or conduit 1120 provides a branch connection for the fuel gas flowing from reducing valve 116. Line 120 is connected at one end to a secondary pressure reducing valve 122 which maintains the fuel gas pressure at about 20 inches of water. Gas flowing directly to the burners takes this route through reducing valve 122. From valve 122 the fuel gas flows through another line 124 connected to the upper frame tube or header 12 by virtue of an appropriate union with the pipe cap 3h.

The other end of line 12% leads to a 3-way control valve 126 the function of which will now be explained. Valve 126 has a line 123 leading therefrom to cylinder 52. Said line 128 is connected to the back side of the piston 58 so that when gas is directed through the control valve 126 to the cylinder the piston 53 is pushed out under gas pressure to swing actuating arm 46 about its pivot on a clamp 38. In this manner the lower frame 5. tube 14 is swung upwardly to raise the heater units off the road surface so that the pavement heater may be moved.

When it is desired to lower the heater units control valve 126 is turned to another position to permit the gas in the cylinder to exhaust itself into the header. The weight of the lower frame tube acting through actuating arm 46 is sufiicient to force piston 58 back into the cylinder and thus force the gas out of said cylinder. Gas being exhausted from cylinder 52 is forced back through line 128, through another position of control valve 126 into a by-pass line 130 which in turn leads through a needle valve 132 into another line 134 which line 134, is joined to a union on header or upper frame tube 12. In short, the control system just described permits the pressurized fuel to be utilized to raise and lower the heater units. No gas being vented from the cylinder 52 is redirected into the main fuel supply line 120 but rather is rerouted through lines 130 and 134 through the needle valve 132. Needle valve 132, of course, allows the gas to be introduced to the header at the correct pressure so that there will be no surges of gas to the heater units. By the above described techniques the propane gas used to do the lifting is not wasted but is allowed to bleed slowly into the gas header. The reducing valve 122 has a built-in relief valve on its downstream side. If needle valve 132 is not throttled properly the surge of pressure causes the excess gas to be vented to the atmosphere through the relief valve. This is to prevent undue pressure surges on the heaters themselves.

The pavement heater may be provided with a reset odometer as shown in FIGURE 7 in order to assist in determining marker spacing. The odometer is mounted on an L-shaped frame member generally shown by reference number 138. The odometer frame 138 is pivotally mounted at its point on a bracket 140 secured to the underside of the clamps 38 which support the push handle 92. Thus one leg 142 of the odometer frame 138 is located adjacent push handle 92 so that the reset meter 146 may be mounted thereon for easy reading. A cable 148 leads from the meter along upper leg 142 and lower leg 144 to the odometer wheel The wheel 150 has a 12-inch circumference so that each revolution thereof will through cable 148 operate a counter mechanism in the meter to indicate how many revolutions and hence how many feet the pavement heater traverses when it is moved. The cable is housed in a cable sheath or conduit and such sheath is held on the odometer frame 138 by a series of spaced apart clips 152.

The pavement heater is operated by turning on the main fuel supply valve 114. Each heater unit 90 is then lighted by turning on each valve outlet 166 on header or frame tube 12 and lighting the burner with a propane torch. When all heater units are burning the pavement heater is moved to the desired location. The control valve 126 is adjusted to a position allowing fuel gas to be vented from the lifting cylinder via the needle valve 132. The heater units are applied to the road surface for a period of 10 to 90 seconds depending on road and weather conditions. The control valve 126 is supported on the push handle 92 so that it can be easily reached by the operator. When the particular spot locations have been heated valve 126 is turned so that gas from tank 110 is directed to the lifting cylinder to lift frame tube 14 and heater units 90. It should be mentioned that the heater unit burners do not rest directly on the surface being heated. The burner elements are spaced from the surface by a skirt which is provided around the burner to hold the burner above the surface and to confine the heat generated by the burner and at the same time to permit adequate venting of exhaust gases.

An alternative embodiment of this pavement heater is shown in FIGURES 8 to 10. Instead of supporting six heater units as shown in the preferred embodiment this particular pavement heater is manually operated and carshaft 236.

ries only two heater units. This particular embodiment of the invention is peculiarly suited to spot heating for marking installations such as crosswalks, stop lines and parking lots.

This pavement heater is comprised of a main body, generally shown by number 200, which is a generally rectangular box frame. Frame 2% is made up of upper longitudinal pieces 202 and 204 and lower longitudinal pieces 202 and 214. The longitudinals are connected at the rear end by transverse pieces 206 and at the front end by transverse pieces 208. The upper and lower longitudinals are connected at the rear end by vertical pieces 212 and in the front end by vertical pieces 210.

The front wheels 216 are supported in wheel yokes 218 which do not swivel. However, the rear casters 220 which are supported in wheel yokes 222 do swivel. A perforated metal sheet or heavy mesh wire is provided between the lower longitudinal and transverse pieces to form a floor or bottom 224 for the frame 200. A cross bar 226 connects the upper horizontal pieces 2612 and 204 approximately at their midpoints. A top surface 228 is formed on frame 260 by providing anotherperforated sheet or heavy mesh between the cross bar 226, the upper rear transverse piece 296 and the upper longitudinals. Thus, the front half of the pavement heater is left open on top for a purpose which will be explained hereinafter. The sides of the frame are also left open.

A U-shaped handle 230 on the rear of frame 200 is supported at the free ends thereof by brackets 232 fixed to the upper rear corner of said frame. Said brackets 232 receive the free ends of handle 230 at an angle so that the handle extends upwardly and rearwardly of frame 200. The handle forms the highest portion of this pavement heater in that the horizontal part of said handle is approximately 35 inches above the road surface.

One side of this pavement heater, i.e. the right hand side in the preferred form, is adapted to carry a pair of heater units of the type used on the six unit pavement heater. To this end a semicircular cradle 234 is provided on each of the two vertical right hand frame pieces 210 and 212. Said cradles 234 are attached to frame 200 so that the lowest point thereof is located at the same general height above the road surface as lower right hand longitudinal frame piece 214.

-A tubular shaft 236 slightly in excess of 6 feet in length is placed in and supported by cradles 234. As can be seen shaft 236 is considerably longer than frame 200 and thus projects forwardly and rearwardly of the frame by about 1 /2 feet. A pair of clamps 238, similar to clamps 38 on the six unit pavement heater are secured to said Toward the rear portion of shaft 236 a shaft handle 240 is rigidly and detachably secured thereto and extends upwardly between the rear end of frame 2% and the push handle 23%. Radiant heater units 242 are mounted on the clamps 238. The radiant heater units 242 connected thereto have flexible fuel line 244 running to a fuel tank 246, preferably a propane cylinder, carried in the forward half of the frame 2011. In actual use a marker heater mechanism 248, not forming a part of this invention and therefore not described in detail, is also mounted beside the fuel tank 246 in the forward half of the frame. The fuel tank is connected by a hose 252 through said marker heater mechanism 248 to the individual supply hoses 244 on the heater units 242.

FIGURES 8 to 10 show the heater units 242 in the lowered or surface heating position. In this position the shaft handle 240 is in a generally upright position. When it is desired to raise the heater units the shaft handle 240 is rotated downwardly so that shaft 236 rotates to lift the heater units off the road surface. The heater units 242 may be held in the raised position by simply swinging the shaft handle and bracing it under the clips 250 attached to the rear upper transverse frame piece 206 (see FIGURE 8). Thus, the heaters will remain raised until the handle 24:) is moved out from under said clip and rotated upwardly.

Since the heater units 242 are connected to the fuel tank 224-6 through said marker heater 248 it is necessary to first light the burner elements in said marker heater before lighting the pavement heater units 242. It should be obvious that a wide variety of spacing may be attained by use of this pavement heater in preparing the road surface for application of road markers.

The foregoing is considered as illustrative only of the principle of this invention. Since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

What is claimed is:

l. A pavement heater for spot heating road surfaces for the application of trafiic markers, comprising:

(a) a supporting frame adapted to be moved about on wheels;

([1) a plurality of individual heater means mounted on said supporting frame;

(c) actuating means to simultaneously raise and simultaneously lower said individual heater means with respect to a road surface;

(d) means carried on said supporting frame for supplying fuel to said individual heater means and said actuating means being connected to said fuel supply means to admit fuel to said actuating means to raise said heater means.

2. A pavement heater for spot heating road surfaces for the application of traffic markers, comprising:

(a) a supporting frame mounted on casters to permit movement over a road surface;

(b) a plurality of individual heater means mounted on one side of said supporting frame;

() actuating means to simultaneously raise and simultaneously lower said plurality of individual heater means with respect to a road surface;

(d) means carried on said supporting frame for Supplying fuel to said individual heater means; said actuating means being connected to said fuel supply means to admit fuel to said actuating means to raise said heater means; and

(a) means for controlling the flow of fuel from said supply means.

3. A pavement heater for spot heating road surfaces for the application of traihc markers, comprising:

(a) a supporting frame mounted on casters to permit movement of said frame over a road surface;

(b) a plurality of individual radiant heater units mounted in line on said supporting frame;

(c) actuating means connected to said supporting frame for simultaneously raising and simultaneously lowering said plurality of individual heater units with re spect to a road surface;

(d) a fuel supply source carried on said supporting frame including means for directing fuel to said plurality of individual heater units; said actuating means being connected to said fuel supply to admit fuel to said actuating means to raise said heater units; and

(e) control means for said means for directing fuel to said plurality of individual heater units.

4. A pavement heater for spot heating road surfaces for the application of traific markers, comprising:

(a) a supporting frame mounted on casters to permit movement of said pavement heater over a road surface;

([1) a tubular frame member movably mounted with respect to said supporting frame;

(0) a plurality of radiant heater units mounted on said tubular frame member so that said heater units are disposed in a line on said supporting frame;

Cir

(d) actuating means to simultaneously raise and simultaneously lower said plurality of heater units with respect to a road surface by movement of said tubular frame member;

(2) a fuel supply source carried on said supporting frame including means for directing fuel from said fuel supply source to said plurality of individual heater units; said actuating means being connected to said fuel supply to admit fuel to said actuating means to raise said heater units; and

(f) control means for said means for directing fuel to said plurality of individual heater units.

5. A pavement heater for spot heating road surfaces for the application of traffic markers thereto, comprising:

(a) a supporting frame mounted on casters to permit movement of said pavement heater over a road surface, said supporting frame including two elongated tubular frame members mounted one above the other in parallel spaced apart relationship, the upper of said tubular frame members having structure secured thereto on which said casters are mounted, the lower of said tubular frame members being swingably supported by said upper tubular frame member;

(b) a plurality of individual heater units mounted in line on said lower tubular frame member;

(c) actuating means to swing said lower tubular frame member to simultaneously raise and simultaneously lower said heater units with respect to a road surface;

(a') a fuel supply means carried on said supporting frame and including means for supplying fuel to said heater units;

(e) one of said tubular frame members being closed at both ends and providing a connecting means between said fuel supply means and said heater units as part of the system for directing fuel to said heater units; and

(1) control means for directing fuel to said plurality of individual heater units.

6. A pavement heater for spot heating road surfaces for the application of traflic markers thereto, comprising:

(a) a supporting frame including a pair of elongated tubular frame members mounted one above the other in parallel spaced apart relationship, the upper of said tubular frame members having structure secured thereto on which casters are mounted for permitting movement of said pavement heater over a road surface, the lower of said tubular frame members being swingably supported by a plurality of arms pivotally connected to said upper tubular frame member;

(b) a plurality of individual heater units mounted in line on said lower tubular frame member;

(0) actuating means connected to one of said plurality of arms for swinging said lower tubular frame member to thereby raise and lower said heater units;

(d) a fuel supply means carried on said supporting frame and including means for directing fuel to said individual heater units; said actuating means being connected to said fuel supply means to admit fuel to said actuating means to raise said heater units; and

(e) control means for regulating the flow of fuel to said heater units.

7. A pavement heater for spot heating road surfaces for the application of traffic markers, comprising:

(a) a supporting frame including a pair of elongated frame members mounted one above the other in substantially parallel spaced apart relationship, the upper of said frame members having structure secured thereto on which casters are mounted for permitting movement of said pavement heater over a road surface, the lower of said frame members being swingably supported by a plurality of arms pivotally connected to said upper frame member;

(b) a plurality of individual heater units mounted in line on said lower frame member;

() actuating means connected to one of said plurality of arms for swinging said lower tubular member to thereby raise and lower said heater units;

(d) a fuel supply means carried on said supporting frame and including means for directing fuel to each of said individual heater units; said actuating means being connected to said fuel supply means to admit fuel to said actuating means to raise said heater units; and

(2) means for controlling the flow of fuel to said heater units.

8. A pavement heater for spot heating road surfaces for the application of traffic markers thereto, comprising:

(a) A supporting frame including a pair of elongated tubular frame members mounted one above the other in substantially parallel spaced apart relationship, the upper of said tubular frame members having structure secured thereto on which casters are mounted for permitting movement of said pavement heater over a road surface, the lower of said tubular frame members being swingably supported by a plurality of arms pivotally connected to said upper tubular frame member, said upper tubular frame member being closed at both ends;

(b) a plurality of individual heater units mounted in line on said lower tubular frame member;

(0) actuating means connected to one of said plurality of arms for swinging said lower tubular frame member thereby to raise and lower said heater units;

(d) fuel supply means carried on said supporting frame and including conduit means for directing fuel from said supply means to said heater units, said closed upper tubular frame member being connected to said conduit means as part of the system for directing fuel to said heater units; and

(e) control means for directing and regulating the How of fuel to said heater units.

9. A pavement heater for spot heating road surfaces for the application of traffic markers thereto, comprising:

(a) a supporting frame including a pair of elongated tubular frame members mounted one above the other in substantially parallel spaced apart relationship, the upper of said tubular frame members having structure secured thereto on which casters are mounted for permitting movement of said pavement heater over a road surface, the lower of said tubular frame members being swingably supported on said upper frame member by a plurality of arms pivotally connected to said upper tubular frame member, said upper tubular frame member being closed at both ends;

(b) a plurality of individual heater units mounted in line on said lower tubular frame member;

((2) actuating means connected to one of said plurality of arms for swinging said lower tubular frame member thereby to raise and lower said heater units;

(d) fuel supply means on said supporting frame and including conduit means for directing fuel from said supply means to said heater units, said closed upper tubular frame member being connected to said conduit means as part of the system for directing fuel to said heater units, said actuating means also being connected to said conduit means to admit fuel to said actuating means to raise said lower tubular frame member; and

(2) control means for directing and regulating the flow of fuel to said heater units and to said actuating means.

10. A pavement heater for spot heating road surfaces for the application of traflic markers thereto, comprising:

(a) a supporting frame including a pair of elongated tubular frame members mounted one above the other in substantially parallel spaced apart relationship, the upper of said tubular frame members having structure secured thereto on which casters are mounted for permitting movement of said pavement heater over a road surface, the lower of said tubular frame members being swingably supported by a plurality of arms pivotally connected to said upper tubular frame member, said upper tubular frame member being closed at both ends;

(1)) a plurality of individual heater units mounted in line on said lower tubular frame member;

(0) actuating means connected to one of said plurality of arms for swinging said lower tubular frame member thereby to raise and lower said heater units, said actuating means including a fluid operated cylinder and piston combination;

(d) pressurized fuel supply means on said supporting frame and including conduit means for directing fuel from said supply means to said heater units, said closed upper tubular frame member being connected to said conduit means as part of the system for directing fuel to said heater units, said conduit means also being connected to said cylinder for directing a portion of said pressurized fuel to said cylinder for actuating said piston to swing said lower tubular frame member, said conduit means also having bypass conduit means for directing fuel exhausted from said cylinder to said heater units; and

(e) control means for directing and regulating the flow of said pressurized fuel from and through said supply and conduit means.

References Cited by the Examiner UNITED STATES PATENTS 3,034,498 5/62 Gillurn 12627l.2 3,055,280 9/62 Neville 12627l.2 X 3,063,442 11/62 Brown 12627l.2

JAMES W. WESTHAVER, Primary Examiner.

PERCY L. PATRICK, Examiner. 

1. A PAVEMENT HEATER FOR SPOT HEATING ROAD SURFACES FOR THE APPLICATION OF TRAFFIC MARKERS, COMPRISING: (A) A SUPPORTING FRAME ADAPTED TO BE MOVED ABOUT ON WHEELS; (B) A PLURALITY OF INDIVIDUAL HEATER MEANS MOUNTED ON SAID SUPPORTING FRAME; (C) ACTUATING MEANS TO SIMULTANEOUSLY RAISE AND SIMULTANEOUSLY LOWER SAID INDIVIDUAL HEATER MEANS WITH RESPECT TO A ROAD SURFACE; (D) MEANS CARRIED ON SAID SUPPORTING FRAME FOR SUPPLYING FUEL TO SAID INDIVIDUAL HEATER MEANS AND SAID ACTUATING MEANS BEING CONNECTED TO SAID FUEL SUPPLY MEANS TO ADMIT FUEL TO SAID ACTUATING MEANS TO RAISE SAID HEATER MEANS. 